Fifty Shades of Phenanthroline: Synthesis Strategies to Functionalize 1,10-Phenanthroline in All Positions

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(11), P. 6700 - 6902

Published: May 15, 2024

1,10-Phenanthroline (phen) is one of the most popular ligands ever used in coordination chemistry due to its strong affinity for a wide range metals with various oxidation states. Its polyaromatic structure provides robustness and rigidity, leading intriguing features numerous fields (luminescent scaffolds, catalysis, supramolecular chemistry, sensors, theranostics, etc.). Importantly, phen offers eight distinct positions functional groups be attached, showcasing remarkable versatility such simple ligand. As result, has become landmark molecule chemists, serving as must-use ligand versatile platform designing polyfunctional arrays. The extensive use substituted phenanthroline different metal ions resulted diverse array complexes tailored applications. For instance, these have been utilized sensitizers dye-sensitized solar cells, luminescent probes modified antibodies biomaterials, creation elegant architectures like rotaxanes catenanes, exemplified by Sauvage's Nobel Prize-winning work 2016. In summary, found applications almost every facet chemistry. An aspect specific reactivity each pair carbon atoms ([2,9], [3,8], [4,7], [5,6]), enabling functionalization Furthermore, it possible differentiate position pairs, resulting non-symmetrical systems tremendous versatility. this Review, authors aim compile categorize existing synthetic strategies stepwise polyfunctionalization positions. This comprehensive toolbox will aid chemists virtually any survey encompass seminal from 1950s present day. scope Review limited 1,10-phenanthroline, excluding more intracyclic heteroatoms or fused aromatic cycles. Overall, primary goal highlight both old recent that find applicability mentioned By doing so, hope establish first reference synthesis, covering all on backbone, inspire concerned devise new not yet explored.

Language: Английский

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Enhanced Visible Light Absorption in Heteroleptic Cuprous Phenanthrolines

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(3), P. 1692 - 1701

Published: Jan. 8, 2024

This work presents a series of Cu(I) heteroleptic 1,10-phenanthroline chromophores featuring enhanced UVA and visible-light-harvesting properties manifested through vectorial control the copper-to-phenanthroline charge-transfer transitions. The molecules were prepared using HETPHEN strategy, wherein sterically congested 2,9-dimesityl-1,10-phenanthrolne (mesPhen) ligand was paired with second phenanthroline incorporating extended π-systems in their 4,7-positions. combination electrochemistry, static time-resolved electronic spectroscopy, 77 K photoluminescence spectra, time-dependent density functional theory calculations corroborated all experimental findings. model chromophore, [Cu(mesPhen)(phen)]+ (1), lacking 4,7-substitutions preferentially reduces mesPhen lowest energy metal-to-ligand (MLCT) excited state. remaining cuprous phenanthrolines (2–4) reduce π-conjugated ligands low-lying MLCT absorption cross sections 2–4 (εMLCTmax = 7430–9980 M–1 cm–1) significantly broadened across visible regions spectrum compared to 1 6494 cm–1). excited-state decay mechanism mirrored those long-lived homoleptic phenanthrolines, yielding three distinguishable time constants ultrafast transient experiments. These represent pseudo-Jahn–Teller distortion (τ1), singlet–triplet intersystem crossing (τ2), relaxed lifetime (τ3). Effective light-harvesting from Cu(I)-based can now be rationalized within strategy while achieving directionality respective transitions, valuable for integration into more complex donor–acceptor architectures longer-lived photosensitizers.

Language: Английский

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Steric and Electronic Influence of Excited-State Decay in Cu(I) MLCT Chromophores

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(19), P. 2872 - 2886

Published: Sept. 11, 2024

ConspectusFor the past 11 years, a dedicated effort in our research group focused on fundamentally advancing photophysical properties of cuprous

Language: Английский

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Changing Directions: Influence of Ligand Electronics on the Directionality and Kinetics of Photoinduced Charge Transfer in Cu(I)Diimine Complexes

Inorganic Chemistry, Journal Year: 2023, Volume and Issue: 62(35), P. 14368 - 14376

Published: Aug. 24, 2023

A key challenge to the effective utilization of solar energy is promote efficient photoinduced charge transfer, specifically avoiding unproductive, circuitous electron-transfer pathways and optimizing kinetics separation recombination. We hypothesize that one way address this develop a fundamental understanding how initiate control directional particularly for earth-abundant first-row transition-metal coordination complexes, which typically suffer from relatively short excited-state lifetimes. Here, we report series functionalized heteroleptic copper(I)bis(phenanthroline) have allowed us investigate directionality intramolecular metal-to-ligand transfer (MLCT) as function substituent Hammett parameter. Ultrafast transient absorption suggests complicated interplay MLCT localization solvent interaction with Cu(II) center state. This work provides set design principles in complexes can be used efficiently connecting molecular modules catalysts or electrodes integration into systems light-driven catalysis.

Language: Английский

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Sterically Encumbered Heteroleptic Copper(I) β-Diketiminate Complexes with Extended Excited-State Lifetimes

Inorganic Chemistry, Journal Year: 2023, Volume and Issue: 62(41), P. 16759 - 16769

Published: Oct. 2, 2023

One of the main challenges in developing effective copper(I) photosensitizers is their short excited-state lifetimes, usually attributed to structural distortion upon light excitation. We have previously introduced charge-transfer chromophores general formula Cu(N^N)(ArNacNac), where N^N a conjugated diimine ligand and ArNacNac substituted β-diketiminate ligand. These were promising regarding tunable redox potentials intense visible absorption but ineffective as photosensitizers, presumably due lifetimes. Here, we introduce sterically crowded analogues these heteroleptic with bulky alkyl substituents on and/or Structural analysis was combined electrochemical photophysical characterization, including ultrafast transient (UFTA) spectroscopy investigate effects groups lifetimes complexes. The molecular structures determined by single-crystal X-ray diffraction display more ground state are into phenanthroline or NacNac ligand, showing smaller τ4 values steric hindrance. UFTA measurements carried out determine dynamics. Sterically encumbered Cu5 Cu6 15-20 times longer than unsubstituted complex Cu1, likely indicating that incorporation inhibits pseudo-Jahn-Teller (PJT) flattening excited state. This work suggests properties can be readily modified dynamics strongly responsive modifications.

Language: Английский

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Photodriven electron-transfer dynamics in a series of heteroleptic Cu(I)–anthraquinone dyads

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(14)

Published: April 14, 2024

Solar fuels catalysis is a promising route to efficiently harvesting, storing, and utilizing abundant solar energy. To achieve this promise, however, molecular systems must be designed with sustainable components that can balance numerous photophysical chemical processes. end, we report on the structural characterization of series Cu(I)-anthraquinone-based electron donor-acceptor dyads. The dyads utilized heteroleptic Cu(I) bis-diimine architecture copper(I) bis-phenanthroline chromophore donor anthraquinone acceptor. We characterized structures complexes using x-ray crystallography density functional theory calculations properties via resonance Raman optical transient absorption spectroscopy. spectroscopy revealed excitation metal-to-ligand charge-transfer (MLCT) transition transfers delocalized ligand orbital. demonstrated each dyad formed oxidized copper-reduced charge-separated state. Unlike most where increasingly bulky substituents phenanthroline ligands lead longer MLCT excited-state lifetimes, here, observe decrease in long-lived state lifetime increasing steric bulk. lifetimes were best explained context electron-transfer rather than energy gap law, which typical for excited states, despite complete conjugation between moieties.

Language: Английский

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Atomistic understanding of enhanced selectivity in photocatalytic oxidation of benzyl alcohol to benzaldehyde using graphitic carbon nitride loaded with single copper atoms

Nanoscale, Journal Year: 2024, Volume and Issue: 16(31), P. 14813 - 14830

Published: Jan. 1, 2024

The enhanced selective oxidation of benzyl alcohol to benzaldehyde under visible light is achieved through atomically precise control the coordination structure single copper atoms on graphitic carbon nitride.

Language: Английский

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Electronic Structures and Photoredox Chemistry of Tungsten(0) Arylisocyanides

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(14), P. 1978 - 1989

Published: June 29, 2023

ConspectusThe high energy barriers associated with the reaction chemistry of inert substrates can be overcome by employing redox-active photocatalysts. Research in this area has grown exponentially over past decade, as transition metal photosensitizers have been shown to mediate challenging organic transformations. Critical for advancement photoredox catalysis is discovery, development, and study complexes based on earth-abundant metals that replace and/or complement established noble-metal-based photosensitizers.Recent work focused 3d metals, containing these most likely would scalable. Although low lying spin doublet ("spin flip") excited states chromium(III) metal-to-ligand charge transfer (MLCT) copper(I) relatively long lifetimes, electronic many other fall dissociative potential surfaces, owing population highly energetic σ-antibonding orbitals. Indeed, we investigators singlet triplet robust closed-shell are too short-lived at room temperature engage bimolecular reactions solutions. In principle, problem could designing constructing strong field π-acceptor ligands, where thermally equilibrated MLCT or intraligand might well below upper surfaces 3d-3d states. Notably, such design elements exploited very recent iron(II) systems. Another approach, one actively pursued, construct 5d vertical excitation 5d-5d ground state geometry require energies far above minima As requirement met tungsten(0) arylisocyanides, focus our aimed development photosensitizers.In following Account, review homoleptic arylisocyanides. Originally reported group 45 years ago, W(CNAr)6 exceptionally large one- two-photon absorption cross-sections. One- produces long-lived (hundreds nanoseconds microsecond) yields. These states, which reductants E°(W+/*W0) = -2.2 -3.0 V vs Fc[+/0], photocatalysis both visible near-infrared (NIR) light. Here, highlight principles led three generations photosensitizers; discuss steps mechanism a prototypal W(CNAr)6-catalyzed base-promoted homolytic aromatic substitution reaction. Among applications bright luminophores, imaging two-photon-initiated polymerization ones plan pursue.

Language: Английский

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Cooperative, Close and Remote Steric Effects on the Structural and Optical Properties of Copper(I) Bis‐Phenanthroline Complexes

European Journal of Inorganic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 20, 2024

Abstract The synthesis as well the structural, optical and computational characterization of seven new highly hindered homoleptic copper(I) phenanthroline complexes (namely C1 – C7 ) is reported along with comparison benchmark derivatives. Despite limited steric hindrance in direct proximity coordination site, X‐ray structures show that higher derivatives series display a more optimal tetrahedral geometry minimal D 2 symmetry distortion. A novel remote control geometry, away from leads to favorable arrangement demonstrated by structural data. In addition, electrochemical steady‐state time‐resolved photophysical studies are presented which further support beneficial effects on ground‐state redox excited‐state properties when both close exploited. Indeed, an increase photoluminescence quantum yield prolongation excited state lifetime observed for highly‐substituted derivative C6 compared counterparts account reduced flattening distortions imparted additional constraints.

Language: Английский

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Tris(aminomethyl)phosphines and Their Copper(I) (Pseudo)halide Complexes with Aromatic Diimines—A Critical Retrospection

Pharmaceuticals, Journal Year: 2023, Volume and Issue: 16(5), P. 766 - 766

Published: May 19, 2023

Metal complexes feature a wide range of available geometries, diversified lability, controllable hydrolytic stability, and easily rich redox activity. These characteristics, combined with the specific properties coordinated organic molecules, result in many different mechanisms biological action, making each myriads classes metal coordination compounds unique. This focused review presents systematized results studies group copper(I) (pseudo)halide aromatic diimines tris(aminomethyl)phosphines general formula [CuX(NN)PR

Language: Английский

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